Method for treatment of penetratable or porous material, and products produced thereby



11 Claims. (Cl. 117-142) This invention relates to a novel method forthe treatment of materials, penetratable or porous in nature, with amodified amino-formaldehyde resin of the type de scribed hereinafter indetail, and a water soluble or water dispersible high molecular weightorganic compound containing at least one sulfo group. The invention alsoineludes novel products resulting from the method of this invention. Themethod and products of this invention are of particular importance inthe leather industry.

Objects and advantages of the invention will be set forth in parthereinafter and in part will be obvious herefrom, or may be learned bypractice with the invention, the same being realized and attained bymeans of the steps, methods, combinations and improvements pointed outin the appended claims.

The invention consists in the novel steps, methods, combinations andimprovements herein shown and described.

An object of my invention is to provide a novel method for filling thepores of a material which is penetratable or porous in nature. A furtherobject of this invention is to provide a novel method for improving thesmoothness of a material which is penetratable or porous in nature. Astill further object of this invention is to provide a novel method forimproving the fullness and tensile strength of leather products. Afurther object is to provide novel products formed in accordance withthe methods set forth in the foregoing objects.

It has been found that the aforementioned objects may be realized byapplying to the penetratable or porous material, hereinafter referred toas porous material, a cationic active modified amino-formaldehyde resinof the type disclosed in my parent application Ser. No. 311,149, filedSept. 23, 1952, now US. Patent No. 2,944,046, of which this applicationis a divisional application, and an anionic active high molecular weightsulfo compound containing at least one sulfo group per molecule, andcausing said modified amino-formaldehyde resin and said sulfo compoundto react to form a water-insoluble reaction product which becomes fixedto said porous material. As will be readily observed from thedescription of the invention hereinafter, the sulfo compound used in theaforedescribed method may be in the form of a neutral salt or may have afree sulfo group.

Since the method of this invention is of particular importance in thetreatment of leather, the present specification will be concernedchiefly with respect to the treat ment of materials relating to theleather industry. It should be realized, however, that the principles ofthis invention are applicable to any porous material, such, for example,as paper, fabrics, and the like.

In the treatment of leather products and the like, the modifiedamino-formaldehyde resin and sulfo compound are dispersed on the leatherand absorbed thereby by means of an aqueous bath whereby they reactunder acidic conditions to form a water insoluble compound N..l.,assignor to James N.J., a corporation of New nice which becomes fixed tothe leather. This improves the fullness, tensile strength and smoothnessof the grain of the treated leather.

Hence, if the sulfo compound is in the form of a neutral salt, the sulfocompound and modified aminoformaldehyde resin are put in an aqueous bathand the leather is treated in said bath for a sufiicient period of time,usually three or four hours, until the sulfo compound and modifiedamino-formaldehyde resins have had time to be absorbed by the leather.Of course, either the modified amino-formaldehyde resin or sulfocompound may be dispersed on the leather in sequence instead ofsimultaneously if so desired, but it is advantageous to treat theleather simultaneously for the time of treatment is shortened. When boththe neutral salt of the sulfo compound and the modifiedamino-formaldehyde resin have been absorbed by the leather, an acidiccompound, such as sulfuric acid, citric acid, lactic acid, diglycolicacid, etc., or an acidic salt such as aluminum sulfate, aluminumchloride, sodium bisulfate is added to the bath to bring the pH of thebath to a definite acidic environment, for example a pH of about 3 or 4,whereupon the sulfo compound and modified amino-formaldehyde resin reactforming a water insoluble compound which remains fixed to the leather.

When a sulfo compound is used which has a free sulfo group so as to beacidic in nature, the sulfo compound and modified amino-formaldehyderesin cannot be added to the bath simultaneously due to the acidicnature of the sulfo compound, a reaction would take place immediately,whereby a water insoluble compound would be formed in the bath, and asuflicient amount of said compound would not be absorbed by the leather.Hence, when a sulfo compound having the sulfo group in the free state isused, the leather must be treated with either the sulfo compound ormodified amino-formaldehyde resin first, and subsequently with theother, but not simultaneously.

Illustrative examples of sulfo compounds which may be used are ligninsulfonate and its neutral salts such as sodium sulfo lignin andmagnesium sulfo lignin; vegetable tannins such as wattle extractsolubilized by sodium bisulfite as well as quebracho extract solubilizedby sodium bisulfite, and the neutral water soluble salts of theseextracts; and synthetic tannins, known as exchange tannins, having atleast one sulfo radical. Included in these exchange tannins are both theacid tannins having a free sulfo group as well as the water solublesalts such as the sodium salts.

The above exchange tannins, preferably include the tannins formed byjoining two moles of compounds such as phenol, cresol, xylenol,naphthol, catechol, resorcinol, naphthalene, anthracene and benzidinebridged with a methylene, sulfone, proplene or sulfonimido bridge. Atleast one mole of the phenol, cresol etc. compounds contain a sulfogroup. Illustrative examples of these compounds are: disulfo dinaphtholmethane, disulfo dinaphthyl methane, monosulfo dihydroxy diphenylmethane, a complex reaction product formed by reacting monosulfodihydroxy methane with formaldehyde to give the formula:

HO- OH HO OH 3 CHz -CH CH -SO5H omega sulfonate of dihydroxy dimethyldiphenyl sulfone, omega sulfonate of dihydroxy diphenyl sulfone, omegasulfonate of dihydroxy diphenyl propane, disulfo dihydroxy diphenylpropane, disulfo dihydroxy diphenyl sulfone, and complex compoundscontaining a benzidine radical with a sulfonimido bridge as illustratedby the following compound:

Q -OO Q The water soluble salts of these compounds are also operablesuch as sodium, potassium and ammonium salts as illustrated by thesodium salt of disulfo dinaphthyl methane, the sodium salt of disulfodihydroxy diphenyl propane and the sodium salt of disulfo dihydroxydiphenyl sulfone.

As indicated heretofore, the modified amino-formaldehyde resins used inthis invention are those resins disclosed in my aforementioned patentapplication Ser. No. 311,149. More particularly, the modifiedamino-formaldehyde resins are those formed by reacting (a) anaminoformaldehyde resin containing unreacted free methylol groups with(b) a water-soluble amino base, said amino base being present in suchamounts whereby all of the methylol groups on the amino-formaldehyderesin are reacted thus providing a cationic-active modifiedaminoformaldehyde resin which is highly stable in an aqueous medium andwill not polymerize or condense therein even on the application of heat.The hereinbefore mentioned amino-formaldehyde resins containing freemethylol groups are Well known water-soluble or water-dispersible resinsformed by the condensation of an amino compound having functional groupswith suitable amount of an aldehyde, preferably formaldehyde, with orwithout a catalyst, at temperatures generally above room temperature.

The preferred modified amino-formaldehyde resins are those formed by thereaction of (a) an amino-formaldehyde resin containing free methylolgroups selected from the group consisting of urea-formaldehyde resins,thiourea-formaldehyde resins, dicyandiamide-formaldehyde resins,acetylene diurea formaldehyde resins and melamine-formaldehyde resinswith (b) a water-soluble amino base selected from the group consistingof urea, thiourea, guanidine, acetylene diurea, melamine anddicyandiamide.

In forming the modified amino-formaldehyde resins used in accordancewith this invention, the molar proportion of the amino base which isreacted with the aminoformaldehyde resin will of course vary dependingupon the number of reactive methylol groups in a molecule of said resinas Well as the number of functional amino groups in the amino base. Theproportions should be such that all of the reactive methylol groups arereacted with an equal number of functional amino groups in the aminobase.

In forming the modified amino-formaldehyde resins, the reaction ispreferably carried out at temperatures between the range of 75 C. to C.Also, the time of the reaction will vary in different cases, the timebeing usually in the range of about 3 to about 10 hours. As is wellknown, the time may be decreased by increasing the temperature and viceversa. The pH of the reaction medium is preferably slightly acid,neutral or slightly alkaline in nature, i.e., about at least 7.Preferably, an

alkaline catalyst such as borax is used to speed up the reaction.

In order to illustrate the invention by working examples, the followingexamples are now given. Examples A-P are directed to the preparation ofmodified aminoformaldehyde resins used in accordance with my presentinvention. If so desired, the modified amino-formaldehyde resins may beprepared in the presence of an anionic active sulfo compound which isneutral as illustrated by Examples Q-V. This is advantageous for themodified amino-formaldehyde resin which is formed and the sulfo compoundare already combined and may immediately be dispersed in an aqueous bathfor treatment of leather in a manner described in detail hereinbefore.Examples 1 to 12 are directed to the manner of treating leather with themodified amino-formaldehyde resins and high molecular weight sulfocompounds in accordance with the present invention.

Example A 180 grams lguanidine carbonate and 243 grams formaldehyde(37%) are mixed together in a flask equipped with reflux and refluxed ata temperature of C. for 1 hour. 168 grams dicyandiamide are then addedand the mixture is refluxed at 80 C. for 6 hours, the pH of the finalreaction product being about 10.5.

Example B 180 grams guanidine carbonate and 243 grams formaldehyde (37%)are heated together in a flask equipped with reflux, the temperaturebeing brought up to 80-90 C. for 1 hour. 126 grams of melamine are addedand the mixture is heated and refluxed 4 hours at 95 C., the pH of thefinal reaction product being about 10.3.

Example C 180 grams guanidine carbonate and 243 grams formaldehyde (37%)are heated together in a flask equipped with reflux, at a temperaturefrom 80 to C. for 1 hour. 228 grams thiourea are then added and themixture is heated and refluxed for 4 hours at 90 C., the pH of the finalreaction product being about 9.8.

Example D 180 grams guanidine carbonate and 243 grams formaldehyde (37%)are heated together in a flask equipped with reflux, the temperaturebeing brought to 80 to 90 C. for 1 hour. 180 grams urea are then addedand the mixture i heated and refluxed for 4 hours at 90 C., the pH ofthe final reaction product being about 9.9.

Example E 126 grams melamine and 489 grams formaldehyde (37%) are heatedtogether in a three neck flask equipped with reflux and the temperatureis raised to 80 C. for /2 hr. 360 grams of guanidine carbonate are thenadded and the mixture is heated and refluxed for 5 hours at C., the pHof the final reaction product being about 9.5.

Example F 60 grams urea and 162 grams formaldehyde (37%) are heatedtogether in a flask equipped with a reflux condenser. The temperature isbrought to 80 C. for 1 /2 hours. 360 grams guanidine carbonate and 200cc. water are then added and the mixture is heated and refluxed for 5hours at 80 C., the pH of the final reaction product being about 10.2.

Example G grams urea, 648 grams formaldehyde (37%) and 38 grams boraxare heated together in a flask equipped with a condenser, at atemperature of 80 C. for 1 /2 hours. 84 grams dicyandiamide are thenadded and the mixture is heated and refluxed for 3 hours at 80 C. Tothis product which has no cation active properties are F o added 84grams dicyandiamide and the heating is continued for 4 hours at 95 C.,the pH of the final reaction product being 9.0.

Example H 142 grams acetylene di-urea, 325 grams formaldehyde (37%) and1.4 grams borax are heated together in a flask equipped with reflux, thetemperature being brought to 95 C. for 4 hours. 180 grams guanidinecarbonate are added and the mixture is heated and refluxed for 2 hoursat 95 C., the pH of the final rejection product being 10.3.

Example I 142 grams acetylene di-urea and 324 grams formaldehyde (37%)are added together in a flask equipped with reflux and 12 grams NaOH 40B6. are added to bring the pH of mixture to 10-12.

The product is agitated for /2 hour until the solution is clear at atemperature 50 to 60 C. 63 grams melamine are then added and the mixtureis heated and refluxed for 2 hours at 95 C. 168 grams dicyandiarnide areadded and the mixture refluxed for 2 hours at 95 C., the pH of the finalreaction product being about 9.0.

Example J 284 grams acetylene di-urea, 652 grams formaldehyde (37%) and1.25 grams borax are mixed in a flask and refluxed for 4 hours at 85 C.under stirring.

470 grams of the final product formed above are mixed With 168 gramsdicyandiamide. This mixture is heated and refluxed for 11 hours in aflask equipped with a reflux keeping the temperature at 95 C. The pH ofthe final reaction product is 8.1.

Example K 84 grams dicyandiamide, 324 grams formaldehyde (37%) and 1.2grams borax are mixed in a flask and heated and refluxed for 4 hours at95 C.

142 grams di-acetylene urea powder are added and the mixture is heatedand refluxed for 10 hours at 95 C the pH of the final reaction productbeing about 8.5.

Example L 168 grams dicyandiamide, 648 grams of formaldehyde (37%) and3.6 grams of borax are mixed and heated and refluxed at 95 C. for 3 /2hours.

336 grams of dicyandiarnide are added and the mixture is heated andrefluxed for 9 hours at 90 C. to 95 C., the pH of the final reactionproduct being 9.7.

Example M 84 grams of dicyandiamide are mixed with 324 grams offormaldehyde (37%) and 1.6 grams of borax. The mixture is heatedtogether in a flask equipped With reflux at a temperature of 95 C. for 4hours.

The mixture is cooled and 180 grams of guanidine carbonate and 208 gramsWater are added. The resulting mixture is heated and refluxed for 3hours at 95 C the pH of the final reaction product being about 10.1.

Example N 84 grams of dicyandiamide, 324 grams of formaldehyde (37%) and1.2 grams of borax are mixed and heated together in a flask equippedwith reflux.

The temperature is brought to 95 C. for 3 hours, the pH at the end ofthe reaction being 8.5.

240 grams of urea are added and heated and refluxed at 95 C. for 5hours, the pH of the final reaction product being 9.9.

Example 0 84 grams of dicyandiamide, 162 grams of formaldehyde (37%) and1.2 grams of borax are mixed and heated together at 95 C. for 25 to 30minutes to form a dicyandiamide-formaldehyde resin. In theabove-described reaction, the heating is controlled in such a manner soas to form a water-soluble reaction product. When 1 cc. of theaforedescribed reaction medium at the beginning of the reactien isintroduced into 100 cc. of cold water, there results a clear solution.When the reaction has progressed for 25 to 30 minutes, 1 cc. of thereaction medium when introduced into 100 cc. of Water imparts thereto acloudy appearance, thus indicating that the amino modifying agent shouldbe added in order to prevent the formation of a water-insolubleamino-formaldehyde resin.

To the above-described dicyandiamide-formaldehyde resin are added 120grams of urea (amino modifying agent) and the resulting mixture isheated for 2 hours at 95 C.

Subsequently, 324 grams of CH O (37%) are added and the reaction iscompleted by heating further for 4 hours at 95 C., the pH of the finalreaction product being 8.0.

Example P 84 grams of dicyandiamide and 162. grams of formaldehyde (37%)are heated together in a flask equipped with a reflux. The mixture isheated at 95 C. for 25 to 30 minutes to form adicyandiamide-formaldehyde resin after which an amino-modifying agent isadded for rea sons mentioned in detail in Example 0.

To the above-described dicyandiamide-formaldehyde resin are added 120grams of urea and the resulting mixture is heated for 2 hours at 95 C.

Subsequently 16.2 grams of formaldehyde (37%) are added and the reactionis completed by heating further for 4 hours at 95 C., the pH of thefinal reaction product being 8.9.

Example Q 180 grams of guanidine carbonate, 243 grams of formaldehyde(37%) and 1580 grams of the sodium salt of disulfo dinaphthyl methane in35% Water solution are heated and refluxed at C. for 1 hour. 168 gramsof dicyandiarnide are then added and the temperature is raised to 95 C.and refluxed for 6 hours. The pH of the final mixture is 10.5.

Example R 1580 grams of the sodium salt of disulfo dinaphthyl methane in35% Water solution are heated under reflux at 95 C. With 324 grams offormaldehyde (37%) and 84 grams of dicyandiamide for 4 hours. 142 gramsof diacetylene urea are then added and the mixture is then heated at 95C. for 8 hours, the pH of the final mixture being 8.5.

Example S grams urea, 243 grams formaldehyde (37%) and 15 grams boraxare heated together in a flask equipped with a reflux. The temperatureis being brought to 80 C. for 1 /2 hours. 63 grams melamine and 500grams of the sodium salt of disulfo dinaphthyl methane in 35% watersolution are added to the above product. The product is then heated andrefluxed for 4 hours at 80 C.

Example T 63 grams melamine, 243 grams formaldehyde (37%) and 790 gramssodium salt of disulfo dinaphthyl methane in 35 Water solution are mixedand heated together in a flask equipped with reflux.

The temperature is then brought to 80 C. for 1 hour and 180 grams ureaare then added and the mixture is heated and refluxed at 80 C. for 4hours.

Example U 42 grams dicyandiamide, 162 grams formaldehyde (37%) and 500grams sodium salt of disulfo dihydroxy diphenyl propane in 50% Watersolution are mixed and heated together in a flask equipped with reflux.

The temperature is then brought to C. for 4 hours.

7 84 grams dicyandiamide are then added and the resulting mixture isheated and refluxed for 9 hours at 95 C.

Example V 84 grams dicyandiamide, 324 grams formaldehyde (37%) and 1.8grams borax are mixed and heated together in a fiask equipped withreflux.

The temperature is brought to 95 C. for 4 hours. 142 grams diacetyleneurea are then added and the resulting mixture is heated and refluxed for1 hour at 95 C. To this mixture is added 1,000 grams sodium salt ofdisulfo dihydroxy diphenyl sulfone in 50% water solution and theresulting mixture is heated and refluxed for hours at 95 C.

Example 1 100 pounds of calf skin, chrome tanned and shaved, are putinto a drum containing an aqueous washing solution and are Washed forhour. The drum is drained and 13 lbs. of a mixture prepared inaccordance with Example U is added, said mixture comprising adicyandiamide-formaldehyde resin modified by dicyandiamide and thesodium salt of disulfo dihydroxy diphenyl propane solution. Sevengallons of water are added along with the above mixture. The skins arethen treated with the bath for 1 hour. /2 pound of sulfuric acid 66 B.is then added bringing the pH of the bath to about 3. The skins are leftin the acid bath for hour during which period a water insoluble compoundis precipitated on the skins. The skins are then washed for /2 hour andare fat liquored with 4 lbs. of sulphonated sperm oil.

Example 2 100 pounds of calf skins, chrome tanned and shaved, are putinto a drum containing an aqueous washing solution and are washed for Ahour. The drum is drained and 4 lbs. of a modified amino-formaldehyderesin prepared in accordance with Example L, along with 7 gallons ofwater, are added to the drum, said amino-formaldehyde resin being adicyandiamide formaldehyde resin modified by dicyandiamide. The skinsare treated with the resin bath for 1 hour, after which, 10 lbs. of 50%solution of disulfo-dihydroxy diphenyl propane are added to the bath andthe skins are left in the bath for /2 hour during which period a waterinsoluble compound is precipitated on the skins. The skins are thenwashed and fat liquored with 4 lbs. of sulphonated sperm oil.

Example 3 10 pounds of calf skin, chrome tanned and shaved, are put intoa drum containing a washing solution and are washed for hour. The drumis drained and 12 lbs. of a mixture prepared in accordance with ExampleQ is added along with 7 gallons of water, said mixture comprising aguanidine-formaldehyde resin modified by dicyandiamide and the sodiumsalt of disulfo-dinaphthyl methane. The skins are then treated with thebath for 1 hour, after which, /2 pound of sulfuric acid 66 B. is addedand the skins are left in the bath for 4 hour during which period awater insoluble compound is precipitated on the skins. The skins arethen washed for /2 hour and are fat liquored with 4 lbs. of sulphonatedsperm oil.

Example 4 100 pounds of calf skins, chrome tanned and shaved, are putinto a drum containing a washing solution and are washed for hour. Thedrum is drained and 3 lbs. of a modified amino-formaldehyde resinprepared in accordance with Example A are added along with 7 gallons ofwater, said resin being a guanidine-formaldehyde resin modified bydicyandiamide. The skins are then treated with the resin bath for 1hour, after which 7 lbs. of disulfo dinaphthyl methane in percent watersolution are added to the bath and the skins are left in the bath for /2hour during which period a water insoluble compound is precipitated onthe skins. The skins are then washed and fat liquored with 4 lbs. ofsulphonated sperm oil.

Example 5 pounds of calf skin, chrome tanned and shaved, are put into adrum containing a washing solution and are washed for A1 hour. The drumis drained and 14 lbs. of a mixture prepared in accordance with ExampleR is added, said mixture comprising a dicyandiamide-formaldehyde resinmodified by diacetylene urea and the sodium salt of disulfo dinaphthylmethane. Seven gallons of water are added along with the above mixture.The skins are then treated with the bath for 1 hour. /2 pound ofsulfuric acid 66 B. is then added. The skins are left in the bath for Ahour during which period a water insoluble resinous compound isprecipitated on the skins. The skins are then washed and are fatliquored with 4 lbs. sulphonated sperm oil.

Example 6 100 pounds of calf skins, chrome tanned and shaved, are putinto a drum containing a washing solution and are washed for hour. Thedrum is drained and 3 lbs. of a modified amino-formaldehyde resinprepared in accordance with Example K along with 7 gallons of water areadded to the drum, said resin being a dicyandiamideformaldehyde resinmodified by diacetylene urea. The skins are treated With the resin bathfor 1 hour, after which 6 lbs. of disulfo-dinaphthyl methane are addedto the bath and the skins are left in the bath for /2 hour during whichperiod a water insoluble resinous compound is precipitated on the skins.The skins are then washed and fat liquored with 4 lbs. sulphonated spermoil.

Example 7 100 pounds of calf skins, chrome tanned and shaved, are putinto a washing solution and are washed for hour. The drum is drained and12 lbs. of a mixture prepared in accordance with Example S is added,said mixture comprising a urea-formaldehyde resin modified by melamineand the sodium salt of disulfo dinaphthyl methane in 35 water solution.Seven gallons of water are added along with the above mixture. The skinsare then treated with the bath for 1 hour. /2 pound of sulfuric acid 66B. is then added and the skins are left in the bath for A hour duringwhich period a water insoluble compound is precipitated on the skins.The skins are then washed for /2 hour and are fat liquored with 4 poundsof sulphonated sperm oil.

Example 8 100 pounds of calf skin, chrome tanned and shaved, are putinto a drum containing a washing solution and are washed for A1 hour.The drum is drained and 13 pounds of a mixture prepared in accordancewith Example T is added, said mixture comprising a melamine-formaldehyderesin modified by urea and the sodium salt of disulfo dinaphthyl methanein 35% water solution. Seven gallons of water are added along with theabove mixture. The skins are then treated with the bath for 1 hour. /2lb. of sulfuric acid is then added and the skins are left in the acidbath for A hour during which period a water insoluble compoundprecipitated on the skins. The skins are Washed for /2 hour and are fatliquored with 4 pounds sulphonated sperm oil.

Example 9 100 pounds of calf skin, chrome tanned and shaved, are putinto a drum containing a washing solution and are Washed for A1. hour.The drum is drained and 13 lbs. of a mixture prepared in accordance withExample V is added, said mixture comprising a dicyandiamideformaldehyderesin modified by diacetylene urea and the sodium salt of disulfodihydroxy diphenyl sulfone in 50% water solution. Seven gallons of waterare added along 9 with the 'above mixture. The skins are then treatedwith the bath for 1 hour. /2 pound of sulfuric acid 66 B. is then addedand the skins are left in the bath for /4 hour during which period aWater insoluble compound is precipitated on the skins. The skins arethen washed for /2 hour and are fat liquored with 4 pounds of sulfonatedsperm oil.

Example 100 pounds of calf skin, chrome tanned and shaved, are put intoa drum containing a washing solution and are washed for hour. The drumis drained and 3 pounds of a modified amino-formaldehyde resin preparedin accordance with Example N, along with 7 gallons of water, are addedto the drum, said resin being a dicyandiamide-formaldehyde resinmodified by ureau. The skins are tretaed with the resin bath for 1 hour,after which, 7 pounds of disulfo-dihydroxy, diphe-nyl sulfone are addedto the bath and the skins are left in the bath for hour during whichperiod a water insoluble compound is precipitated on the skins. Theskins are then washed and fat liquored with 4 pounds of sulphonatedsperm oil.

Example 11 100 pounds of calf skin, chrome tanned and shaved, are putinto a drum containing an aqueous washing solution and are washed forhour. The drum is drained and 9 pounds of the sodium saltdisuifo-dihydroxy diphenyl propane along with 7 gallons of water areadded to the drum, and the skins are treated with this composition forhour. 4 pounds of a modified amino-formaldehyde resin prepared inaccordance with Example L are then added to the drum bath and the skinsare treated with the bath for 1 hour. /2 pound of sulfuric acid is thenadded to the bath and the skins are left in the acid bath for hourduring which period a Water insoluble compound is precipitated on theskins. The skins are then Washed for /2 hour and are fat liquored with 4pounds of sulphonated sperm oil.

Example I 2 100 pounds of calf skin, chrome tanned and shaved, are putinto a drum containing an aqueous washing solution and are washed for 4hour. The dnum is drained and 9 lbs. of the sodium saltdisulfo-dinaphthyl methane along with 7 gallons of Water are added tothe drum, and the skins are treated with this composition for hour. 4pounds of a modified amino-formaldehyde resin prepared in accordancewith Example A are then added to the drum bath and the skins are treatedwith the bath for 1 hour. V2 pound of sulfuric acid is then added to thebath and the skins are left in the acid bath for A hour during whichperiod a water insoluble compound is precipitated on the skins. Theskins are then washed for /2 hour and are fat liquored with 4 pounds ofsulphonated sperm oil.

The treated leather products obtained by the process disclosed in theabove Examples 1 to 12 have a high degree of fullness and tensilestrength. Other materials which may be treated by this process arepaper, fabrics, woodwork, etc. wherein the water-insoluble compoundprecipitated on the object being treated acts as a filler, modifyingagent, etc.

The invention in its broader aspects is not limited to the specificsteps and compositions described but departures may be made therefromwithin the scope of the accompanying claims without departing from theprinciples of the invention and without sacrificing its chiefadvantages.

This is a divisional application of co-pending application Ser. No.311,149, filed September 23, 1952, now U.S. Patent No. 2,944,046.

What is claimed is:

1. The method of treating a porous material to impart thereto a smoothfinish, comprising applying to said material a water-solublecationic-acid modified aminoforrnaldehyde resin free of unreactedmethylol groups, and an anionic-active, high molecular weight compoundcontaining at least one sulfo group whereby said cationicactive andanionic-active materials are absorbed by said porous material, andcausing said modified amino-formaldehyde resin and said sulfo,containing compound absorbed by said porous material to react to form awaterinsoluble product which becomes fixed to said porous material so asto fill the pores thereof.

2. The method according to claim 1, wherein the modifiedamino-formaldehyde resin is a resin formed by reacting (a) a resinselected from the group consisting of urea-formaldehyde resins,thiourea-formaldehyde resins, guanidine-formaldehyde resins, acetylenediurea-formaldehyde resins, melaminedormaldehyde resins anddicyandiamide-formaldehyde resins with (b) awater-soluble amine baseselected from the group consisting of urea, thiourea, guanidine,acetylene diurea, melamine and dicyandiamine, the water-soluble aminobase being in an amount suificient to react with all of the methylolgroups of the amino-formaldehyde resin, said reactions being carried outat a pH of about at least 7.

3. The method according to claim 2, wherein said sulfo compound is selcted from the group of water soluble salts of a high molecular weightsulfo compounds and high molecular weight sulfo compounds having freesulfo radicals.

4. The method according to claim 3, wherein the sulfo compound is aneutral salt of a high molecular weight sulfo compound and in which theacid environment is provided by the addition of an acid to said bathafter the resin and sulfo compound have been dispersed on said porousmaterial being treated.

5. The method according to claim 3, wherein the sulfo compound is a highmolecular weight sulfo compound, having a free sulfo group, said porousmaterial being impregnated first with the modified amino-formaldehyderesin and then with the sulfo compound, said sulfo compound beingsufiiciently acidic to provide the necessary acidic environment for thereaction of said modified resin and said sulfo compound on said porousmaterial.

6. The method according to claim 4, wherein the porous material is firsttreated with a neutral high molecular weight sulfo compound and then themodified aminoformaldehyde resin.

7. The method according to claim 3, wherein the porous material isleather.

8. The method according to claim 7, wherein the sulfo compound is thesodium salt of disulfo dinaphthyl methane.

9. The method according to claim 7, wherein the sulfo compound is thesodium salt of disulfo dihydroxy diphenyl propane.

10. The method according to claim 7, wherein the sulfo compound is thesodium salt of disulfo dihydroxy diphenyl sulfone.

11. A coated porous material having a smooth finish comprising a porousmaterial having absorbed thereon a water-insoluble reaction productfixed to said porous material so as to fill the pores thereof, saidwater-insoluble reaction product formed by the reaction on said porousmaterial of a water-soluble cationic-active modified amino-formaldehyderesin free of unreacted methylol groups, and an anionic-active, highmolecular weight compound containing at least one sulfo group.

References Cited in the file of this patent UNITED STATES PATENTS2,452,536 Kirk Nov. 2, 1948 2,601,671 Wilson et al June 24, 19522,646,419 Suen et al. July 21, 1953 2,721,145 Cheronis Oct. 18, 1955UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,024,136 March 6, 1962 Lucien Sellet It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 2, line 54, for "proplene" read propylene column line 44, for"gmount" read amounts line 69, for "10 C." read 110 C. column 9, line15, for 'ureau" read urea line 16, for "tretaed" read treated column 10,line 1, for "cationic-acid!:Jr'ead cationic active lines 8 and 9, after"water-insoluble insert reaction Signed and sealed this 24th day of July1962.

SEAL) lttest:

ERNEST w. SWIDER DAVID LADD tttesting Officer Commissioner of Patents

1. THE METHOD OF TREATING A POROUS MATERIAL TO IMPART THERETO A SMOOTHFINISH, COMPRISING APPLYING TO SAID MATERIAL A WATER-SOLUBLECATIONIC-ACID MODIFIED AMINOFORMALDEHYDE RESIN FREE OF UNREATED METHYLOLGROUPS, AND AN ANIONIC-ACTIVE, HIGH MOLECULAR WEIGHT COMPOUND CONTAININGAT LEAST ONE SULFO GROUP WHEREBY SAID CATIONICACTIVE AND ANIONIC-ACTIVEMATERIALS ARE ABOSORBED BY SAID POROUS MATERIAL, AND CAUSING SAIDMODIFIED AMINO-FORMALDEHYDE RESIN AND SAID SULFO CONTAINING COMPOUNDABSORBED BY SAID POROUS MATERIAL TO REACT TO FORM A WATERINSOLUBLEPRODUCT WHICH BECOMES FIXED TO SAID POROUS MATERIAL SO AS TO FILL THEPORES THEREOF.